A new interpolation equalization scheme for discrete wavelet multitone modulation/demodulation systems

Discrete Wavelet Multitone (DWMT) Modulation provides an alternative to the conventional Discrete Multitone (DMT) Modulation in various Digital Subscriber Line (xDSL) applications. The DWMT systems permit a high level of spectral containment and exhibit high robustness to narrowband noise and variations in channel frequency response characteristics. In this paper, an effective equalization scheme is presented for DWMT systems. Hitherto equalization schemes are based on pre- or post-detection equalization, optimization of the filterbank at the receiver, or combined optimization of filterbanks at the transmitter and receiver ends. In this paper, by taking into account the dominant effects of the non-integer channel delay, the pre- and post-detection equalization techniques are combined to obtain a novel interpolation equalization scheme. Simulation results show that the proposed technique results in a relative high Signal-to-Interference Ratio (SIR) and low computation complexity with one-tap interpolation equalization, leading to a high SIR close to the ideal channel case with multi-tap interpolation equalization.